Of all the dance-world's spectres, none is quite so ever-present as that of Serge Diaghilev, founder of the Ballets Russes. Bringing together a brilliant and diverse set of choreographers, composers, and designers, the Russian impresario initiated many of the greatest artistic collaborations of the modern age. Dance-company directors have been trying to do the same ever since. Presenting his Morphoses project last month, the choreographer Christopher Wheeldon was the latest in a long line to cite Diaghilev as an inspiration.

These days, though, as two sell-out shows last week demonstrated, the really effective mixing and shaking is done behind the scenes. Hofesh Shechter's In Your Rooms is the result of a collaboration among the artistic directors of three London venues: the Place, the Queen Elizabeth Hall, and Sadler's Wells. From modest beginnings in March, the project was expanded at each subsequent venue, culminating in a final showing at Sadler's Wells which had a youthful crossover audience (the grail of all dance marketeers) stamping and cheering for more.

Shechter's work repays, in full, the investment made in it. In Uprising, seven male dancers rage against the vastness of the cosmos, and as they're hurled around on the precision tide of Shechter's choreography, show you what a brave and ludicrous thing it is to be a man. They fight, run like apes, cling to each other, take refuge in elaborate and fearful ritual. And all of it to a slamming pulse which dares you to look away. Shechter is a concert-level percussionist, and although he's only been making dance for five years, no other choreographer combines such a thrilling command of rhythm with such subtle manipulation of spatial dynamics. In Your Rooms intercuts passages of extreme delicacy - a trio of women with ribboning arms, a kneeling frieze, a softly waving anemone cluster - with moments of chthonic grimness. With dark, reptilian crawls, obsessively repeated gestures and freaked-out spasms of existential terror. And the clothes! Grey socks, cargo pants, and nerdy sweaters. Is there a point to it all? No says Shechter, only the void. But he has you on the edge of your seat, dry-mouthed, from start to finish.

In Your Rooms was followed on Wednesday by Cast No Shadow, a collaboration between choreographer Russell Maliphant and film-maker Isaac Julien. The two were brought together by a Sadler's Wells commission, and the final work was co-produced by the New York arts organisation Performa. Again, the show had a cutting-edge, fashionable audience scrambling for tickets. Again, it left them wanting more.

The first piece, True North, places us in a landscape of black and white, of rock and snow and meltwater. As films of polar landscapes show on a three-screen array, dancers perform slow and beautiful convolutions. Bodies become rigid as corpses, are carried like provisions, are supported, lowered and dropped. Like the pole itself, the dancers freeze and melt, and as the piece progresses its message becomes more overtly political.

Julien's clearly expressed notion of the world's interconnectedness seems to rouse Maliphant from the choreographic comfort zone in which he's languished for the past few years. Although still clearly entranced by a particular and narrow area of craft - supple, boneless line, smooth flowing movement - True North sees him embracing a wider aesthetic. Unlike Shechter, he still ignores the abrasive and grotesque, which this gives the piece a somewhat unvarying character, but it is undeniably lovely to look at.

Small Boats opens with a film of a marine graveyard. We know immediately that these cracked, peeling craft belong to those who have attempted escape from south to north. Sure enough, behind the film-screen, storm-tossed and exhausted figures become visible. This sombre scene, reminiscent of Les Ballets C de la B's Cargo, is beautifully treated by Maliphant, with the dancers' passive sway expressing an entire palette of despair. Film of a flyblown baroque church, which follows, seems to be a metaphor for the decadence these unfortunates will encounter on whatever hostile shore they land. Those who survive, that is, for in a haunting final undersea passage, we see a trio of dancers twisting like expiring tuna in a hanging drift-net. If Small Boats is overlong, the result is resonant and moving. And vitally, much more than the sum of its parts.

What both the Schecter and Maliphant seasons demonstrate is the fast-growing role of theatre management personnel as enablers. If anyone can lay claim to the fur-collared overcoat of Serge Diaghilev, it's probably Alistair Spalding, artistic director of Sadler's Wells, whose enlightened commissions have made him a vital figure in the careers of Matthew Bourne, Akram Khan and Wayne McGregor, as well as Shechter and Maliphant.

A key elements of these relationships is imaginative match-making. Cloistered in the studio, bogged down with touring logistics, sprained ankles and Kafka-esque funding applications, dance-makers can easily miss the wider picture. Many continue in familiar but unproductive thematic grooves, and draw their collaborators from a narrow tranche of personal acquaintances. The results are as underwhelming as may be imagined, and reinforce a contemporary-dance ghetto. Neither Hofesh Schecter nor Russell Maliphant is the type to miss the wider picture, but as these two seasons demonstrate, a little help from on high can go a long way.